COVID-19 and increased thrombosis risk: A therapeutic challenge
24 Feb 2021
LMU cardiologist Steffen Massberg’s Corona Lecture focuses on some of the major complications that can arise in serious cases of COVID-19 and considers their implications for the successful treatment of the disease.
The virus SARS-CoV-2 targets the respiratory tract. In serious cases, the infection can lead to acute respiratory distress, which requires invasive oxygenation. Further complications may then ensue, including pulmonary embolisms and the aberrant formation of blood clots in the veins.
In his contribution to LMU’s Corona Lectures on 2 March 2021, cardiologist Prof. Dr. med. Steffen Massberg will discuss the physiological processes that lead to the emergence of such life-threatening complications. In COVID-19 patients who are at risk of lung failure, inflammatory reactions take place, which activate platelets in the circulation and trigger the process of clotting. This in turn ultimately leads to obstruction of the blood vessels in the lung. Professor Massberg (Director of Medical Clinic I at the LMU Health Center and holder of the Chair of Internal Medicine with a focus on Cardiology at LMU) will outline how, in the context of a SARS-CoV-2 infection, this initially localized ‘immunothrombotic’ process develops into a systemic increase in the risk of blood clotting. He will then review the implications of this clinical progression for the treatment of COVID-19, and suggest possible approaches to the prevention of clot formation.
Lecturer: Prof. Dr. med. Steffen Massberg
Steigendes Thromboserisiko bei COVID-19: eine Herausforderung für die Therapie
At the moment, the incidence of COVID-19 cases in Germany is falling. What is the current situation from the clinical point of view, in particular with respect to patients who require intensive care? Have you noticed any differences between the first wave of the pandemic and the second – with respect to the proportion of severe cases, for example?
Steffen Massberg: Fortunately, the numbers of COVID patients under treatment in the LMU Medical Centers have also fallen significantly – over the Christmas season the emergency services were kept busy transferring severely ill COVID-19 patients to hospital. There were times when more than 100 SARS-CoV-2 infected patients were undergoing treatment. Happily, the numbers who require intensive care has also fallen in the meantime. One of the most striking developments in comparison with the first wave is that a significantly larger fraction of the patients infected with the virus are older and more likely to present with comorbidities – nursing homes are prominent hotspots of infection. As a result, mortality has risen in the University Hospitals System. We fervently hope that, thanks to the prioritization of this population for immunization, this trend can be stopped in the coming weeks. –Israel has already published very encouraging data on the efficacy of early vaccination of these individuals.
Patients who require invasive oxygenation are at particular risk of developing intravenous blood clots. Why are these SARS-Cov-2 patients so susceptible to this type of complication?
Steffen Massberg: That is a very interesting question, which we have been studying –albeit in a different context – for many years now. Patients who require artificial respiration must be maintained in an artificially induced state of coma. As a consequence of immobility and other factors, these patients have an intrinsically higher risk of developing thromboses, quite apart from the dangers presented by the infection itself. In addition, as we and other research groups have demonstrated experimentally in animal models, the activation of the immune system is closely linked to increased susceptibility to clot formation. This concept of ‘immunothrombosis’ can in part explain why patients with chronic inflammatory conditions or infections have a greater tendency to develop clots that obstruct blood flow. The interactions between clotting factors, thrombocytes and cellular constituents of the immune system appear to play a particularly prominent role in serious cases of COVID-19. Under such circumstances, clots can form not only in the lungs, but also in the kidneys and in the heart. This in turn contributes to the multifaceted clinical course of the disease, which can lead to impairments of multiple organ systems.
What are the major challenges in the treatment of COVID-19 patients? Have more effective strategies been developed than those that were available at the time of the first wave of the disease – for the prevention of clot formation and other complications, for instance?
Steffen Massberg: Evidence-based medicine depends on the use of large-scale randomized clinical studies, which make it possible to decide which of the available interventions is “the most effective”. In the case of a condition that first emerged little more than a year ago, we don’t really have enough reliable data to follow this route. Nevertheless, based both on our own experiences and on the recommendations of specialized panels, clinical care of COVID-19 patients includes careful monitoring of patients with respect to enhanced risk of clotting, particularly in the case of complications such as lung embolisms and heart attack. These patients receive drugs that inhibit the process of clot formation, which should reduce the risk of thromboses. Our COVID teams on intensive care units, observation wards and normal wards now have a great deal more experience of, and expertise in responding to the clinical course of the disease than in the first few months of the pandemic. And with dexamethasone, we now have an efficacious therapeutic option to hand.
Prof. Dr. med. Steffen Massberg holds the Chair of Internal Medicine with a Focus on Cardiology at LMU, and is the Director of Medical Clinic I at the LMU Medical Center. His research interests are concerned with aspects of the immune response in the context of chronic inflammatory diseases.